All depends on your goals and whether or not you want to spike that insulin PWO. If you are just doing a food based meal with protein and complex carbs, probably around 1-1.5 hr pwo is good. If you are wanting the "spike" then usually that is immediately pwo. (I know the dreaded pwo spike...but for recovery it works for me...)

What I do is make the pwo drink, sip 1/3 pre workout....1/3 during...and 1/3 after. Now this is for my schedule of heavier lifting....as I am not in a weight loss mode, although I am gaining muscle and not too much fat....as long as I watch what I eat for the rest of the day.

Again, all depends on your goals and training. But I would guess the soreness may be a sign of not recovering quick enough.